A mounting plate of an access terminal box is a mounting accessory of the access terminal box and has a wide range of application scenarios. The mounting plate is configured to be assembled on the access terminal box, so as to mount the access terminal box on a specified position. The mounting plate may support wall-hung mounting, in-wall mounting, and dedicated slide mounting in a cabinet or a chassis, and may also support mounting by directly attaching the mounting plate to a wall by using an adhesive tape. Specifically, when the access terminal box is being mounted, it is required to first fasten the access terminal box on the mounting plate and then fasten the mounting plate on a specified position. However, when it is required to detach the access terminal box from the mounting plate, it is required to manually separate a mounting member on a base of the access terminal box. As a result, a detaching operation is inconvenient, and when a separating force is too large, damage is caused to a part on the base of the access terminal box. In addition, because a large quantity of fibers are coiled on the base of the access terminal box, when the separating force is too large during detachment, a fiber may be touched, which causes damage to the fiber.